1. Field of the Invention
This invention relates to gas generators and is particularly directed to solid propellant gas generators for producing high electron density gases for utilization in magnetohydrodynamic (MHD) systems.
2. Description of the Prior Art
Gas generators for the production of high electron density gases for utilization in MHD systems are based upon: (1) liquid propellant systems seeded with aqueous solutions of potassium or cesium salts (e.g. KNO.sub.3, CsNO.sub.3, Cs.sub.2 CO.sub.3), or (2) solid propellant gas generators which have the potassium or cesium salts directly incorporated into the propellant matrix.
The liquid propellant systems are limited in the magnitude of electrons produced by two factors. First, the flame temperatures are limited to approximately 3300.degree. K. since metallic fuels are not present. The generation of electrons from the ionization of the alkali molecules present (M.fwdarw.M.sup.+ +e.sup.-) where M=K or Cs, is very exponentially temperature dependent. Second, the ratio of hydrogen to carbon present in the liquid fuel ranges from 1 to 2 depending upon the fuel's character (aromatic versus aliphatic). The water produced during combustion dissociates at high temperatures (H.sub.2 O.fwdarw.OH+H), followed by the secondary reaction in which electrons are attached (OH+e.sup.31 .fwdarw.OH.sup.-), thereby reducing the effective free electron concentration.
Solid propellant electron gas generators based upon double-base binders highly loaded with oxidizers such as HMX which contain alkali salts such as KNO.sub.3 and/or CsNO.sub.3 and a metallic fuel have been developed. However, the hydrogen content of these solid propellants is still high due to the intrinsically high hydrogen content of the binder and especially the HMX, but flame temperatures are attained which exceed those of the liquid propellant systems by hundreds of degrees since a metallic fuel is present.